The aqueous solubility of trichloroethene (TCE) and tetrachloroethene (PCE) as a function of temperature

Using a flexible Au bag autoclave and a precision high-pressure liquid chro matography pump to control pressure, the liquid-liquid aqueous solubilities of TCE and PCE were measured as a Function of temperature from 294 to 434 K (at constant pressure). The results were used to calculate the partial mo lal thermodynamic quantities of the organic liquid aqueous dissolution reac tions: Delta (G) over bar(soln), Delta (H) over bar(soln) and Delta (C) ove r bar (soln). Calculated values for these quantities at 298 K for TCE are: Delta (G) over bar(soln) = 11.282 (+/-0.003) kJ/mol, Delta (H) over bar(sol n) = -3.35 (+/-0.07) kJ/mol, Delta (S) over bar = -49.07 (+/-0.24) J/mol K, and Delta (C) over bar(soln) = 385.2 (+/-3.4) J/mol K. Calculated values f or these quantities at 298 K for PCE are: Delta (G) over bar(soln) =15.80 ( +/-0.04) kJ/mol, Delta (H) over bar(soln) = -1.79 (+/-0.58) kJ/mol, Delta ( S) over bar(soln) = -59.00 (+/-1.96) J/mol K and Delta (C) over bar(p soln) = 354.6 (+/-8.6) J/mol K. These thermodynamic quantities may be used to ca lculate the solubility of TCE and PCE at any temperature of interest. In th e absence of direct measurements over this temperature range, the Henry's L aw constants for TCE and PCE have been estimated using the measured aqueous solubilities and calculated vapor pressures. (C) 2000 Published by Elsevie r Science Ltd. All rights reserved.